Automatic validity checking and type identification of banknotes - uses light diodes and photosensitive detectors to identify characteristic transparency patterns in tracks across the notes

摘要

The network for automatically checking the validity of and also of identifying the value of banknotes uses a set of LED's and photo-sensitive detectors arranged in an array across the path of the banknote, and an evaluation circuit which identifies characteristic patterns of transparency in tracks across the bank note. The number, typically three, of light diode and photosensitive detector pairs (d,d2) are arranged across the path of a banknote (204) moving between two guides (202). An additional pair of diode and detector pairs (1D, 1E) detects the front edge of the banknote and controls the timing the evaluation network (441) to which the amplified gated and time integrated photosensitive detector signals (PA, PB, PC) are fed. The output of the evaluation network is used together with other signal derived from magnetic (JA, JB, JC) dimension and colour disdriminator networks to feed the final evaluation network (442) which generates outputs corresponding to the various banknote type appropriate to the equipment.